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OK... I am starting a new thread because I want to post some pics (at bottom) specifically related to my HVAC sub's ductwork so far (you are welcome 41gasman!) He has rectified a lot, but there is still some stuff I am not pleased with. I base this on reading here, and on Internet research on good flex duct design/install.

I'd like to ask comments on the pics because I am going to get them fixed. The sagging is easily bad, but others may be open to argument. Esp. if I am a consumer -- via my GC who is onboard w/ this -- telling an "HVAC pro" it needs re-work.

Specific concerns:
1) duct passing over duct in subfloor cavities -- he may say that only the outside R6 insulation layer is crushed, not the inner air-bearing layer.
True? ..or comments I can counter with would be appreciated.

2) In many, many places -- and I have no pics here -- instead of using a 3-seam elbow to feed a vertical-boot outlet, they have used mitred floor-boot outlets instead. I have read that this sharp right-angle on the inside turn of the mitred boot causes CFM turbulence at the exit and adds an eqiv. length 40 feet longer than the other way. I want them removed and replaced with 90-corners and vert. boot outlets. Comments?

As I have posted before, this is an energy efficient ICF home. We are not going to cut corners and the HVAC guy says he will do what he needs to do to make us happy. That is very good! So, I want to be informed and fair when I bring these points up.

As far as i can remember, you can cut a hole up to 2/3 the size of the TGI joist as long as you do not cut the top or bottom of the "I Beam" part. But I do agree, that hole is much bigger than that. Suprised that the inspector did not sqauk a little on that. The ductwork looks messy, but functional.

I've seen worse, it's hard to tell with some of pics because I can't see more of the duct run. On the one he just needs another strap. On the one going up to the sub floor it looks like it is going into a register boot and dosn't seem that bad. The one that over laps the other is hard to tell from the pic if it is crushed bad enough so that it will cause a major problem. The Y fitting should be fine, but tough to say with out seeing more. As far as the holes I'm sure they are acceptable. I like to use all galv pipe on my jobs, it works and looks better. So this isn't the way I would have done it either. Make sure the flex is supported good at all the bends it will be likely to kink some over time.

All of these pics are from the first floor, looking up at the 2nd floor subfloor above the kitchen, pantry, downstairs bedroom and garage -- which has a media room above it. Space was limited due to design of home. You can see it all from Day-1 at http://billusa.********.com but it will take awhile.

I will check on the TGI joist hole issue -- it's news to me. The holes for the largest duct pass-thru's are well within 1" at the top and bottom where the beams are. I guess I need to do some more Googling to educate myself there too!

As to "crushed bad enough" where they pass over-under: there is about 1/2-3/4" compression on each outer surface of the R6 -- the duct surfaces that touch each other and then the top surface pressed against the bottom of the 2nd floor subfloor.

Question #2- I use these 90 degree boots all the time with no problems. It seems to me that there are other problems that need your attention more. If you want a 90 elbow and straight boot at every register its going to be below the bottom of the floor truss and I don't think you will be able to tell any difference from one to the other.

Originally posted by trane He means a boot that is usually called a 90 degree or angle boot which is used in all houses by most contractors because a straight boot and elbow will hang below the bottom of the floor joist.